Soluble particulate matter (PM) components such as metals have the potential to be absorbed into the bloodstream and transported to the heart where they might induce inflammatory effects or other cardiac problems, reported that soluble Zn and V can produce physiological changes in cardiac myocytes. Many commuters of the Mexico City Metro may spend as long as 3 h in the underground subway facilities. In addition, there are stations where various types of consumer goods can be bought such as pizzas, burgers and other Mexican-styled dishes. Therefore, the exposure to high concentrations of respirable and fine particles and especially to high concentrations of metals such as Fe, Cu and Cr, could represent a significant health risk to vulnerable groups, causing cumulative or chronic health effects over time.